"""
Complete the Bag class from the given class defition. Work with a partner
if you can. You can do it on paper, or on a computer. Try it on a computer
is encouraged.

You may skip the implementation for the iterator for now.
"""
class Bag:

    def __init__ ( self ):
        """ Create an empty Bag """
        pass

    def len(self):
        """Return the length of the bag (count of the bag)"""
        pass

    def add(self , item ):
        """ Adds an item to the bag. What if it does not fit? """
        pass

    def remove (self , item ):
        """ removes an item from the bag and returns it.
        What to do if its not in there ? return None ? Exception ? """
        pass

    def contains (self , item ):
        """ checks if an item is in the bag , returns True or False """
        pass

    def iterator ( self ):
        """ returns an iterator for the bag """
        pass